Re: [PATCH 3/3] NFSD: Enable NFS server use of PF_INET6

["J. Bruce Fields" <bfields@fieldses.org>]

On Fri, Jan 22, 2010 at 12:07:42PM -0500, Chuck Lever wrote:
>
> On Jan 21, 2010, at 5:07 PM, J. Bruce Fields wrote:
>
>> On Fri, Jan 15, 2010 at 06:17:38PM -0500, Chuck Lever wrote:
>>>
>>> On Jan 15, 2010, at 5:44 PM, J. Bruce Fields wrote:
>>>
>>>> On Wed, Jan 13, 2010 at 04:10:48PM -0500, Chuck Lever wrote:
>>>>> Try to use an PF_INET6 listener for NFSD if IPv6 is enabled in the
>>>>> kernel.
>>>>>
>>>>> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
>>>>> ---
>>>>>
>>>>> fs/nfsd/nfsctl.c |   36 +++++++++++++++++++++++++++++-------
>>>>> fs/nfsd/nfssvc.c |   27 ++++++++++++++++++++++-----
>>>>> 2 files changed, 51 insertions(+), 12 deletions(-)
>>>>>
>>>>> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
>>>>> index 2604c3e..7ebb7a5 100644
>>>>> --- a/fs/nfsd/nfsctl.c
>>>>> +++ b/fs/nfsd/nfsctl.c
>>>>> @@ -981,6 +981,26 @@ static ssize_t __write_ports_delfd(char *buf)
>>>>> 	return len;
>>>>> }
>>>>>
>>>>> +static ssize_t __write_ports_create_xprt(struct svc_serv *serv,
>>>>> +					 const char *transport,
>>>>> +					 const int family,
>>>>> +					 const unsigned short port)
>>>>> +{
>>>>> +	int err;
>>>>> +
>>>>> +	err = svc_create_xprt(serv, transport, family, port,
>>>>> +						SVC_SOCK_ANONYMOUS);
>>>>> +
>>>>> +	if (err < 0) {
>>>>> +		/* Give a reasonable perror msg for bad transport string */
>>>>> +		if (err == -ENOENT)
>>>>> +			err = -EPROTONOSUPPORT;
>>>>> +		return err;
>>>>> +	}
>>>>> +
>>>>> +	return 0;
>>>>> +}
>>>>> +
>>>>> /*
>>>>> * A transport listener is added by writing it's transport name and
>>>>> * a port number.
>>>>> @@ -1000,14 +1020,16 @@ static ssize_t __write_ports_addxprt(char
>>>>> *buf)
>>>>> 	if (err != 0)
>>>>> 		return err;
>>>>>
>>>>> -	err = svc_create_xprt(nfsd_serv, transport,
>>>>> -				PF_INET, port, SVC_SOCK_ANONYMOUS);
>>>>> -	if (err < 0) {
>>>>> -		/* Give a reasonable perror msg for bad transport string */
>>>>> -		if (err == -ENOENT)
>>>>> -			err = -EPROTONOSUPPORT;
>>>>> +	err = __write_ports_create_xprt(nfsd_serv, transport, PF_INET,
>>>>> port);
>>>>> +	if (err < 0)
>>>>> 		return err;
>>>>> -	}
>>>>> +
>>>>> +#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
>>>>> +	err = __write_ports_create_xprt(nfsd_serv, transport, PF_INET6,
>>>>> port);
>>>>> +	if (err < 0 && err != -EAFNOSUPPORT)
>>>>> +		return err;
>>>>> +#endif	/* CONFIG_IPV6 || CONFIG_IPV6_MODULE */
>>>>
>>>> Does every caller of __write_ports_create_xprt() with PF_INET6 end  
>>>> up
>>>> being under this ifdef?  Could we instead just move the ifdef inside
>>>> it
>>>> (or inside __svc_xpo_create())?  (As usual I'd rather keep any
>>>> necessary
>>>> hidden away to the extent possible.)
>>>
>>> The only two call sites are right here:  one with PF_INET and one  
>>> with
>>> PF_INET6.
>>
>> OK, but svc_create_xprt has a few more.
>>
>>>
>>> When IPv6 support is not enabled, we want only the first call (with
>>> PF_INET).  When IPv6 support is enabled, we want two calls; one with
>>> PF_INET and then one with PF_INET6.
>>
>> Right, I understand, but we could equally well do that by calling
>> svc_create_xprt twice, and depending on it (or __svc_xpo_create(), or
>> someone else there) to return -EAFNOSUPPORT in the ! 
>> defined(CONFIG_IPV6)
>> && !defined(CONFIG_IPV6_MODULE case.  Right?
>>
>> No change in behavior, I just want the #ifdef's buried a little  
>> further
>> if it's possible.
>
> Yeah, OK.  That kind of change would effect other call sites, so I would 
> need to break this into a couple of smaller patches.

Yes, that sounds right.

--b.